(1) Field of the Invention
The present invention relates to a communication system for transmitting handwriting either mainly or supplementarily, using computers which are connected via a network, and to a handwriting input device and a handwriting display device used in such a handwriting communication system, and more specifically to an optimal system for the handwriting communication in a TV conference system, and for a telecommunicative coaching school which utilizes the Internet, and to a handwriting input device and a handwriting display device used in the system.
(2) Description of the Related Art
In recent years, since the Internet has become increasingly popular, a shift from a conventional coaching school to a new mode of a home study coaching school is groped. The conventional coaching school is one in which students come to the coaching school to study. The new mode of the home study coaching school is one in which students together with a teacher proceed to study through telecommunications on the Internet. For the home study coaching school, it is desired to actualize the handwriting communication system through which an answering sheet written by the student can be seen by the teacher in a real time base.
For this kind of home study coaching school system, a touch panel system or a handwriting input pad on which one can make a direct input on the liquid crystal display directly with a dedicated purpose pen can be used. However, since most of conventional answering means employ a sheet of paper, the way of study by the electronic pen and a liquid crystal display is too different from the normal way of study at school or at home, and thus the introduction of the electronic pen and the liquid crystal display is difficult for children to accept.
Another way of transmitting the answering sheet in which the image of a handwritten answering sheet is sent through a facsimile or TV conference system can be considered. However, since there is a large quantity of information in the whole answering sheet, the transmitting time of the information sometimes takes from a few seconds to a few minutes, so that it is difficult for a teacher to deal with the student on a real time base. Furthermore, although on the conventional TV conference system, it is possible to confirm the face of student, when a camera of the TV conference system takes a picture of the answering sheet, the resolution of the camera is not enough to confirm the letters written or filled out on the answering sheet, so that the TV conference system is not suitable for transmitting the answering sheet on a real time base.
There is a handwriting input device to input the information written on paper into a computer, called xe2x80x9cCrosspadxe2x80x9d by IBM Corporation. In this device, a ballpoint pen is equipped with a communicator to generate an electric wave. When handwriting is conducted on the paper placed on a pad by the ballpoint pen, a plurality of coils embedded in the pad detect the electric wave of the ballpoint pen to locate a position of the pen tip of the ballpoint pen. By tracing the detected position of the pen tip, the handwriting information is obtained as vector information simultaneously with handwriting on the paper, and then this information may be memorized in the Crosspad unit or transmitted to the computer.
In these kinds of handwriting input devices, however, since a special dedicated purpose pen is used, a regular writing instrument sold at a store cannot be used. In other words, the writing instrument usually used by each person, or the special shape pencil used to correct the gripping of a pencil cannot be used for these input devices. Furthermore, the devices do not have an eraser function to erase handwriting, so that the input could not be conducted in such a manner that a person usually writes and erases with a pencil and an eraser. With these restrictions, the conventional devices cannot easily be used by anyone from children to aged persons.
Further, in the case where these input devices are used for a handwriting communication system, since the communicated information becomes vector information only, a document that is already written or a designated section of a printed matter cannot be sent. Moreover, since the transmittable information is vector information only, the information transmitted does not represent the line thickness of the letter or the color thereof.
Therefore, a handwriting communication system which allows to electrically transmit in real time the handwritten information input by using a pencil or erased by using an eraser, has been desired.
An object of the present invention, therefore, is to overcome the problems existing in the prior art, and to provide a handwriting communication system, and a handwriting input device, as well as, a handwriting display device used therein, which can communicate through handwriting among a plurality of computers connected via a network. The object of the present invention is further to provide an inexpensive handwriting communication system, handwriting input device and handwriting display device which allow commercially available writing instruments to be used freely. The object of the present invention is still further to provide a system and a device which can transmit a document that is already filled out, or a designated portion or all of a printed matter. More particularly, the object of the present invention is to provide a system and a device which are suitable for a telecommunicative coaching school to study at home.
According to one aspect of the invention, there is provided a handwriting communication system, which transmits and receives a handwriting with the use of a plurality of computers connected via a network, and is comprised of a handwriting input device provided at a transmitting side computer in order to input the handwriting information into the transmitting side computer, and a handwriting display system which is provided at a receiving side computer in order to display the handwriting based on the handwriting information transmitted to the receiving side computer. The handwriting input device is comprised of a trace display means in which the information to be transmitted is written, an input means for writing/erasing or designating the handwriting in the trace display means, an image taking means to take from above the image of the trace display means, a position detecting means to detect the pointed position when the input means is placed on the trace display means, and an image processing means to extract a contiguous or adjoining image around the pointed position of the input means which is detected by the position detecting means from the whole image taken by the image taking means and to generate contiguous image information. The handwriting display device is comprised of an image reconstruction means to reconstruct the image based on the contiguous image information extracted by the image processing means and the position pointing information detected by the position detecting means, and the handwriting display means to store and display the reconstructed images on the display screen.
The present invention also relates to a handwriting input device comprised of an input means to enter a handwriting or to erase a handwriting, a trace display means to display the trace accompanied with the operation of the input means, an image taking means to take from above the whole image of the trace display means, a position detecting means to detect the position of the input means when it is placed on the trace display means, and an image processing means to extract a contiguous image of the pointed position of the input means detected by the position detecting means from the whole image taken by the image taking means.
The present invention further relates to a handwriting display device comprised of an image reconstructing means to reconstruct the image based on the contiguous image and the pointed position information, and a trace display means to store the reconstructed images and display them on a display screen. The image reconstructing means is equipped with a display memory corresponding to the display screen and generates an address from the pointed position information and data from the contiguous image information, and they are stored and displayed on the display screen by writing the data on the address in the display memory.
The position detecting means is comprised of a retroreflective material which is provided at the tip of the input means, and a light source which is provided near the image taking means to irradiate the input means, and detects the pointed position of the input means which is placed on the trace display means by detecting the position of the retroreflective material based on the differences in brightness of images taken by the image taking means.
The retroreflective material provided at the tip of the input device is either provided in at least two places with a space therebetween, or is provided in such a way that a narrow and long image is taken by the image taking means. The image processing means detects the direction or the orientation of the input means from the shape of the retroreflective material whose image is taken by the image taking means, and the image processing means removes the image of the input means from the extracted contiguous image based on the detected direction of the input means.
Otherwise, the shape of the retroreflective material is either predetermined by the kinds of the input means, or changed by the operation of the operator, and the image processing means changes the sizes of extracted contiguous images in accordance with the shapes, and processes them.
Further, color filters may be provided on the front of the reflective surface of the retroreflective material. Either the light source can be changed to emit a plurality of colors of light or the image taking means is capable of detecting color, and by distinguishing the plurality of retroreflective materials, the kinds of the plurality of input means are distinguished.
The image processing means also removes the fourth quadrant portion of the extracted contiguous image.
The image reconstruction means is equipped with a display memory corresponding to the display screen. It generates an address from the pointed position information and data from the contiguous image information, and stores and displays the trace on the trace display means on the display screen by writing the data on the address in the display memory.
The image taking means is either provided in the upper left corner or in the upper right corner of the trace display means for a right-handed operator or a left-handed operator respectively.
The image processing means can be provided within the transmitting side computer or receiving side computer.
A generally used TV conference system sacrifices resolution to reduce communication volume, so that when an image of the whole sheet is taken, details become difficult to identify. The present system according to the invention, however, transmits only a contiguous image around the handwritten portion, which reduces the communication volume compared to transmitting the whole image, which makes the real time transmission and reception of handwriting trace possible. Moreover, the reduction of data volume does not result from lowering resolution, so that it becomes possible to provide a handwriting communication system which can transmit detailed portions.